Experimental performance of EUV multilayer flight mirrors for AIA

Experimental performance of EUV multilayer flight mirrors for AIA

UCRL-PROC-218841
Experimental performance of EUV multilayer flight mirrors for AIA
Regina Soufli1*, David L. Windt2†, Jeff C. Robinson1, Sherry L. Baker1,
Eberhard Spiller1, Franklin J. Dollar3, Andrew L. Aquila3, Eric M. Gullikson3,
Benjawan Kjornrattanawanich4, Charles Brown5, John F. Seely5,
Bill Podgorski6, Leon Golub6
1Lawrence
Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550
2Columbia Astrophysics Laboratory, New York, NY 10027
3Lawrence Berkeley National Laboratory, Berkeley, CA 94720
4Universities Space Research Association, National Synchrotron Light Source,
Beamline X24C, Brookhaven National Laboratory, Upton, NY 11973
5Space Science Division, Naval Research Laboratory, Washington, DC 20375
6Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138
*[email protected]; phone 925-422-6013; fax 925-423-1488
† Current affiliation for D.L. Windt: Reflective X-ray Optics, New York, NY 10027
Introduction
¾
Multilayer coatings for the 7 EUV channels of the AIA have been
developed1 and completed successfully on all AIA flight mirrors.
Mo/Si coatings (131, 171, 193.5, 211 Å) were deposited at
Lawrence Livermore National Laboratory (LLNL). SiC/Mg (304,
335 Å) and Mo/Y (94 Å) coatings were deposited at Columbia
University
¾
EUV reflectance of the 131 / 335 Å, 171 Å, 193.5 / 211 Å primary
and secondary flight mirrors and the 94 / 304 Å secondary flight
mirror was measured at beamline 6.3.2. of the Advanced Light
Source (ALS) at LBNL
¾
EUV reflectance of the 94 / 304 Å primary and secondary flight
mirrors was measured at beamline X24C of the National
Synchrotron Light Source (NSLS) at Brookhaven National Lab.
Preliminary EUV reflectance measurements of the 94, 304 and
335 Å coatings were performed with a laser plasma source
reflectometer located at Columbia University
¾
1
Multilayer-coated AIA flight
mirror pair at 335 Å (SiC/Mg,
left) and 131 Å (Mo/Si, right)
Prior to multilayer coating, Atomic Force Microscopy (AFM)
characterization and cleaning of all flight substrates was
performed at LLNL
R. Soufli, D. L. Windt, J. C. Robinson, E. A. Spiller, F. J. Dollar, A. L. Aquila, E. M. Gullikson, B. Kjornrattanawanich,
J. F. Seely, L. Golub “Development and testing of EUV multilayer coatings for the atmospheric imaging assembly
instrument aboard the Solar Dynamics Observatory”, Proc. SPIE 5901, 59010M (2005).
AFM data on flight substrates at LLNL determine surface roughness
and reveal morphology associated with specific polishing techniques
100000
Tinsley SN002 secondary substrate
(prior to coating with 94/304 Å)
100000
AIA-1001-002
10×10 µm2, locs.
A, B, (Tinsley)
C, D
Sagem 04R0416 primary substrate
(prior to coating with 131/335 Å)
Primary 04R0416 (Sagem)
10×10 µm2, locs. A, B, C, D, E
2×2 µm2, locs. A, B, C, D
2×2 µm2, locs. A, B, C, D, E
1000
4
4
PSD (nm )
PSD (nm )
1000
10
0.1
0.0001
10
0.001
0.01
-1
Spatial frequency (nm )
10×10 µm2, loc. B
0.1
2×2 µm2, loc. B
0.1
0.0001
0.001
0.01
-1
Spatial frequency (nm )
10×10 µm2, loc. E
σ = 0.14 nm rms
σ = ∫ 2π f S ( f )df
f1
2×2 µm2, loc. E
σ = 0.51 nm rms
f2
2
0.1
where S(f) ≡ PSD (nm4),
f1= 10 -3 nm-1 , f2 = 5×10-2 nm-1
2-dimensional power spectral density of 10×10 µm2 AFM images
obtained at LLNL on AIA flight substrates
fy (nm-1)
Tinsley SN002 secondary
substrate (94/304 Å), loc. B
Sagem 04R0416 primary
substrate (131/335 Å), loc. E
+0.025
0
-0.025
-0.025
0
Preferential direction
of polishing marks
σ = 0.14 nm rms
-1
+0.025 fx (nm )
Isotropic surface finish
σ = 0.51 nm rms
To maximize mirror performance, multilayer “shadowing”
due to coating masks and fixtures needs to be minimized
¾ “Shadowing” is caused during multilayer deposition by sputtered species bouncing off hardware
parts in the vicinity of the substrate, causing the multilayer to miss thickness/wavelength
specifications in these areas
¾ In the case of the AIA optics, the D-shaped mask is of particular concern for shadowing, which
occurs around the center line of the optic:
(1) Within the substrate region that undergoes multilayer deposition
(2) Underneath the mask, in the region that is expected to remain covered
AIA primary
Region where D-mask
“shadowing” occurs
Coated region
D-mask
AIA secondary
AIA mirrors benefit from D-mask design modifications
17
16
before D-mask modifications:
M4-041209A2
M4-041215A2
15
131 Å
Mo/Si
14
ϕ=180°
after D-mask modifications:
M4-050324A2
M4-050331A2
AIA secondary, r =15 mm
θi= 87 deg
ϕ=270°
15 mm
13
± (0.3 x FWHM131 Å)
12
0
45
90
ϕ=90°
135
180
φ (deg)
225
270
315
360
EUV reflectance measurements vs. azimuth angle are performed at r = 15 mm on a test
AIA secondary to assess improvements in shadowing due to D-mask modifications
171 Å
Mo/Si
ϕ=0
CWHM wavelength (nm)
± (0.3 x FWHM171 Å)
Reflectometry and scattering beamline 6.3.2 (ALS)
Beamline Specifications
• Wavelength precision: 0.007%
• Wavelength uncertainty: 0.013%
• Reflectance precision: 0.08%
• Reflectance uncertainty: 0.08%
• Spectral purity: 99.98%
• Dynamic range: 1010
69.0
70
68.5
Reflectance (%)
60
68.0
50
67.5
12.90
40
12.95
30
13.00
PTB
CXRO
20
Precision Reflectometer
10
0
12.5
13.0
13.5
W avelength (nm)
14.0
• 10 µm × 300 µm beam size
• 10 µm positioning precision
• Angular precision 0.01 deg
• 6 degrees of freedom
• Sample size up to 200 mm
LG156
Peak wavelength and reflectance of 131 Å flight primary meet
specifications in entire clear aperture
134
Clear Aperture at r = 94 mm
Clear Aperture at r = 45 mm
Peak wavelength (Å)
133
± (0.3 × FWHM) = ± 1.4 Å
132
131
130
r = 45 mm
r = 60 mm
r = 75 mm
r = 90 mm
r = 92 mm
r = 94 mm
129
128
127
-45
M4-051116A3
0
45
90
φ (deg)
Peak Reflectance (%)
80
Clear Aperture at r=94 mm
Clear Aperture at r=45 mm
r = 45 mm
r = 60 mm
r = 75 mm
r = 90 mm
r = 92 mm
r = 94 mm
70
60
ϕ=90°
50
θmeas = 87 deg
M4-051116A3
40
335 Å
Mg/SiC
-90
-45
0
φ (deg)
45
90
ϕ=0
-90
ϕ=-90° 131 Å
Mo/Si
θmeas = 87 deg
r
Peak wavelength and reflectance of 131 Å flight secondary
meet specifications in entire clear aperture
134
Clear Aperture at r = 34 mm
Clear Aperture at r = 9 mm
133
Peak wavelength (Å)
± (0.3 × FWHM) = ± 1.4 Å
132
131
130
r = 9 mm
r = 12 mm
r = 20 mm
r = 30 mm
r = 32 mm
r = 34 mm
129
128
127
M4-051116A2
-45
80
Peak Reflectance (%)
θmeas = 87 deg
0
φ (deg)
45
90
335 Å
Mg/SiC
r
Clear Aperture at r=34 mm
Clear Aperture at r=9 mm
70
ϕ=90°
60
r = 9 mm
r = 12 mm
r = 20 mm
r = 30 mm
r = 32 mm
r = 34 mm
50
40
-90
-45
131 Å
Mo/Si
θmeas = 87 deg
M4-051116A2
0
φ (deg)
45
90
ϕ=0
-90
ϕ=-90°
EUV reflectance of flight mirrors is consistent with AFMmeasured substrate roughness
70
Reflectance (%)
60
50
40
M4-051116
A1 (witness,
Si wafer substrate)
θmeas= 87 deg
A2 (secondary,
Sagem 0420 substrate)
Mo/Si, Γ = 0.36
N=50
A3 (primary,
Sagem 416 substrate)
A4 (witness,
Si wafer substrate)
30
20
10
0
120
125
130
Wavelength (Å)
135
Flight mirror
Primary
(Sagem
04R0416)
Secondary
(Sagem
04R0420)
Substrate
roughness
(Å rms)
5.0
5.2
Rpeak (%)
56.2
58.8
∆R*
(%, absolute)
8.5
8.4
Rpeak +∆R
64.7
67.2
140
*∆R = predicted reflectance loss due to high-spatial
frequency roughness, based on AFM measurements of the
substrate and on a multilayer growth model
Measurements of specular EUV reflectance and diffuse
scattering are consistent with each other
Normalized intensity
1
Direction of specular reflectance (R)
AIA flight primary (Tinsley SN003 substrate)
Μo/Si, λ = 210.94 Å
θmeas = 87 deg
Loc. A (r = 90 mm, ϕ = 0°), Rpeak = 31.7 %
0.1
Loc. B (r = 90 mm, ϕ = 60°), Rpeak = 32.2 %
Loc. C (r = 75 mm, ϕ = - 30°), Rpeak = 34.2 %
Loc. D (r = 75 mm, ϕ = 30°), Rpeak = 34.6 %
diffuse scattering
0.01
155
160
165
170
Detector angle, θdet (deg)
175
θmeas= 87 deg
Mo/Si-coated flight mirrors at
193.5 Å (right) and 211 Å (left)
Reflectance, R (%)
30
θdet= 174 deg
Loc. A
20
Loc. B
Loc. C
Loc. D
10
0
180
190
200
210
220
Wavelength (Å)
230
240
94 Å (Mo/Y) / 304 Å (SiC/Mg) flight coatings
335 Å (SiC/Mg) flight coatings
Flight mirrors are shown after 335 Å SiC/Mg
coating is completed (right), prior to
deposition of 131 Å Mo/Si coating
Acknowledgements
•The authors are grateful to the AIA/SDO teams at the Smithsonian
Astrophysical Observatory, Lockheed Martin, and NASA
• This work was performed under the auspices of the U.S. Department of
Energy by the University of California Lawrence Livermore National
Laboratory under Contract No. W-7405-ENG-48. The work at Lawrence
Berkeley National Laboratory was performed under the auspices of the
U.S. Department of Energy under contract No. DE-AC03-76F00098
• Funding was provided by the Smithsonian Astrophysical Observatory